1. Steve Harris SPASH – Biotechnical Engineering Instructor

2. Accuracy is how close a measured value is to the actual (true) value.

3. Precision is how close the measured values are to each other.

5. Group 1 Group 2 Group 3 Group 4 1.01 g 2.863287 g 1.013251 g 2.05 g 1.03 g 2.754158 1.013258 g 0.23 g 0.99 g 2.186357 g 1.013255 g 0.75 g 1.01 g 2.601267 g 1.013255 g 1.01 g

6. Problem 2

7. Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of: 39.4, 38.1, 39.3, 37.5, 38.3, 39.1, 37.1, 37.8, 38.8, 39.0. This distribution shows no tendency toward a particular value (lack of precision) and does not acceptably match the actual temperature (lack of accuracy).

8. Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of: 37.8, 38.3, 38.1, 38.0, 37.6, 38.2, 38.0, 38.0, 37.4, 38.3. This distribution shows no impressive tendency toward a particular value (lack of precision) but each value does come close to the actual temperature (high accuracy).

9. Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of : 39.2, 39.3, 39.1, 39.0, 39.1, 39.3, 39.2, 39.1, 39.2, 39.2. This distribution does show a tendency toward a particular value (high precision) but every measurement is well off from the actual temperature (low accuracy).

10. Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of: 38.0, 38.0, 37.8, 38.1, 38.0, 37.9, 38.0, 38.2, 38.0, 37.9. This distribution does show a tendency toward a particular value (high precision) and is very near the actual temperature each time (high accuracy).

11.  What’s the difference between…..  http://www.theweatherprediction.com/habyhints/ 246/ http://www.theweatherprediction.com/habyhints/ 246/  http://www.butlercc.edu/engineering/en115/en115 _accur_vs_prec.cfm http://www.butlercc.edu/engineering/en115/en115 _accur_vs_prec.cfm  http://www.mathsisfun.com/accuracy- precision.html http://www.mathsisfun.com/accuracy- precision.html